Two homoallyl/cyclopropylalkyl rearrangements accompanying a Wolff-Kishner type reduction

Conceived as a model study for the enantio selective synthesis of the natural product (S)-bakuchiol, the deoxygenation of a recently described trishomoallyl alcohol was attempted using the Kabalka modification of the Wolff-Kishner method after prior oxidation of the alcohol to the ketone. However, an unprecedented succession of homoallyl/cyclopropyl ring closure and ring opening altered the carbon skeleton profoundly. The crucial intermediates are assumed to be radicals although carbanions cannot yet be definitely ruled out. (C) 2001 Elsevier Science Ltd. All rights reserved.